Mitul Abhangi | Searcharxiv

arXiv2026

Development of a thin-target hard X-ray bremsstrahlung detection system to study confined runaway electrons in Aditya-U Tokamak

A specially shielded CdTe detector based hard X-ray (HXR) monitoring system equipped with a lead collimator has been developed and installed on the Aditya-U tokamak to investigate the dynamics of fast electrons (~20-200 keV) generated during sawtooth activity. The pre-existing HXR monitor in Aditya-U is exposed to the entire HXR bremsstrahlung emission from the plasma volume, peripheral limiters, and other structural components, which limits its ability to separately study the dynamics of lost and confined runaway electrons (REs). In contrast, the newly developed diagnostic has successfully measured the chord-averaged thin-target HXR bremsstrahlung emission encompassing the core plasma region, particularly within and around the sawtooth inversion radius. The measured HXR spectra are validated through forward modelling code that incorporates plasma parameters, confined RE characteristics, and the geometric configuration of the diagnostic system. The results confirm the capability of the developed HXR monitor to probe the fast-electron dynamics during internal plasma instabilities.

physics.plasm-ph↗

arXiv2025

Radiation Tolerance Characterisation of an Indigenously Developed p-type Silicon Pad Sensor for Forward Calorimetry Applications

We report on the radiation tolerance characterisation of a p-type silicon pad sensor indigenously designed by BARC-VECC and fabricated at Bharat Electronics Limited (BEL), India -- representing a significant step toward establishing a domestic silicon sensor manufacturing capability for high-energy physics applications. Single-pad test structures were irradiated with neutrons over a range of fluences from $\sim10^{7}$ to $\sim2.5\times10^{14}$~1~MeV~$n_{\mathrm{eq}}$/cm$^{2}$, spanning the operational regime relevant to forward calorimetry in high-luminosity heavy-ion collider experiments. Post-irradiation performance was characterised through systematic measurement of leakage current evolution and calorimetric response as functions of accumulated neutron fluence. A single-exponential annealing model is introduced to describe the time dependence of leakage current within the observation window, and the current-related damage constant $\alpha$ is extracted and compared with the RD48 reference value. The results demonstrate that the sensors survive the target fluence with measurable but recoverable degradation, validating the fabrication process and providing a baseline for future qualification of this indigenous sensor production chain.

physics.ins-det↗